Similarly, the high expression of endogenous osteopontin (OPN) in HCC cells can also promote the polarization of macrophages to the M2-like phenotype, and upregulate the expression of PD-L1 by activating the CSF1/colony-stimulating factor receptor (CSF1R) signaling pathway in macrophages [54]. The gene discussed is SPP1; the disease is hepatocellular carcinoma.